The Influence of Lower Temperature Induction of Valsa mali on the Infection of Apple Trees

Apple valsa canker (AVC), caused by Valsa mali, is one of the most important diseases of apple trees in China. AVC occurred severely along with cold winter or cold spring. However, the effect of lower temperature on V. mali is poorly understood. This study evaluated the influence of lower temperature pretreatment of V. mali on the infection of apple twigs and leaves. The results showed that exposing V. mali to lower temperatures (between -10°C and 10°C) for more than 18 h significantly increased the disease severity of apple leaves and twigs, with a higher lesion area ratio (LAR), lesion length, and disease incidence (DI) than that at 25°C. In addition, cold treatment ranging from -5°C to 10°C promoted colony growth. Meanwhile, the relative expression of four cell wall degrading enzyme (CWDE)-related genes pretreated at -5°C and 5°C were significantly higher than that at 25°C. The results indicated that the virulence of V. mali mycelium is sensitive to lower temperatures. After sensing lower temperature changes, V. mali can adjust its infection of apple trees by regulating the expression of pathogenicity gene and growth rate. Spring has very frequent temperature changes, and V. mali is highly invasive in this season. Therefore, more attention should be paid in spring to protecting apple trees from infection of V. mali, by reducing pruning wound formation in spring and applying protective agents to pruning wounds in time.

Synthesis of liquid fuel via direct hydrogenation of CO2

Synthesis of liquid fuels (C₅₊ hydrocarbons) via CO₂ hydrogenation is very promising. Hydrogenation of CO₂ to liquid hydrocarbons usually proceeds through tandem catalysis of reverse water gas shift (RWGS) reaction to produce CO, and subsequent CO hydrogenation to hydrocarbons via Fischer-Tropsch synthesis (FTS). CO₂ is a thermodynamically stable and chemically inert molecule, and RWGS reaction is endothermic and needs a higher temperature, whereas FTS reaction is exothermic and is thermodynamically favored at a lower temperature. Therefore, the reported technologies have some obvious drawbacks, such as high temperature, low selectivity, and use of complex catalysts. Herein we discovered that a simple Co₆/MnO_x nanocatalyst could efficiently catalyze CO₂ hydrogenation. The reaction proceeded at 200 °C, which is much lower than those reported so far. The selectivity of liquid hydrocarbon (C₅ to C₂₆, mostly n-paraffin) in total product could reach 53.2 C-mol%, which is among the highest reported to date. Interestingly, CO was hardly detectable during the reaction. The in situ Fourier transform infrared characterization and ¹³CO labeling test confirmed that the reaction was not via CO, accounting for the eminent catalytic results. This report represents significant progress in CO₂ chemistry and CO₂ transformation.

Method for Aluminum Oxide Thin Films Prepared through Low Temperature Atomic Layer Deposition for Encapsulating Organic Electroluminescent Devices

Preparation of dense alumina (Al₂O₃) thin film through atomic layer deposition (ALD) provides a pathway to achieve the encapsulation of organic light emitting devices (OLED). Unlike traditional ALD which is usually executed at higher reaction n temperatures that may affect the performance of OLED, this application discusses the development on preparation of ALD thin film at a low temperature. One concern of ALD is the suppressing effect of ambient temperature on uniformity of thin film. To mitigate this issue, the pumping time in each reaction cycle was increased during the preparation process, which removed reaction byproducts and inhibited the formation of vacancies. As a result, the obtained thin film had both high uniformity and density properties, which provided an excellent encapsulation performance. The results from microstructure morphology analysis, water vapor transmission rate, and lifetime test showed that the difference in uniformity between thin films prepared at low temperatures, with increased pumping time, and high temperatures was small and there was no obvious influence of increased pumping time on light emitting performance. Meanwhile, the permeability for water vapor of the thin film prepared at a low temperature was found to reach as low as 1.5 × 10⁻⁴ g/(m²·day) under ambient conditions of 25 °C and 60% relative humidity, indicating a potential extension in the lifetime for the OLED.